Since my page is going to be launched from a website after user login, I need to be able to pass along credentials, headers, user info and other relevant data to the app. Is there a way to capture HttpRequestMessage data inside my app? Is this something I can pull out using javascript?

That turned out to be the way after all. My trouble was that I had set the localstorage while on one tab and tried retrieving it from the app while it was on another tab. So, I modified my Landing page ( as a proof of concept ) to add localstorage info, then redirect to the app. Since it was in the same tab, my app was able find and retrieve the data.